Malonamidooxadethiacephem compounds

ABSTRACT

An antibacterial compound represented by the following formula: ##STR1## (wherein R is a hydrogen atom or a lower alkyl, lower alkenyl, lower alkynyl or lower alkylthio-lower alkyl group; 
     B 1  and B 2  each is a hydrogen atom or an ester or salt forming group or atom same or different for each; and 
     Het is a monocyclic hetero-cyclic group) 
     showing strong antipseudomonal activity, process for preparing the same, pharmaceutical preparation containing the same and method for combating bacterial infection by applying the same.

This invention relates to novel 7β-(substituted malonamido or unsubstituted malonamido)-7α-methoxy-3-heterocyclic thiomethyl-1-oxa-1-dethia-3-cephem-4-carboxylic acid compounds, methods for preparing them, antibacterial use and preparations utilizing the said compounds.

I. COMPOUNDS

More specifically, this invention relates to a compound represented by the following formula: ##STR2## (wherein R is a hydrogen atom or a lower alkyl, lower alkenyl, lower alkynyl or lower alkylthio-lower alkyl group;

B¹ and B² each is a hydrogen atom or an ester or salt forming group or atom; same or different for each; and

Het is a monocyclic heterocyclic group).

Characteristics

The malonamidooxadethiacephem compounds (I) have strong antibacterial activity. They are superior to their analogs (Japanese Published Patent Application No. 133,997/1977) having an aromatic group in place of the R group of the formula (I) in the effect for protecting mice from infections caused by gram-negative bacteria e.g. Pseudomonas aeruginosa, height of blood level, chemical stability and easiness to purify. Thus, the compounds are useful as β-lactam antibacterials for medicines, veterinary drugs, sterilizers, disinfection agents, sanitarizing substances and so forth.

Explanation of Symbols

Preferable substituents R as a lower alkyl, lower alkenyl or lower alkynyl group for the malonamido substituent in the formula (I) include C₁ to C₆ (especially C₁ or C₂)-alkyl, C₂ to C₅ -alkenyl and C₂ to C₅ -alkynyl. Preferable lower alkylthio-lower alkyl group are C₁ to C₂ -alkylthio-C₁ to C₂ -alkyl.

Preferable monocyclic heterocyclic groups Het are 5 or 6-membered ring groups having 1 to 4-hetero atoms (O, N and/or S) optionally substituted e.g. by C₁ to C₅ -alkyl, carboxyalkyl, aminoalkyl, halogen, hydroxy and/or oxo.

B¹ and B² each is a hydrogen atom or a carboxy modification conventional in the chemistry of penicillins and cephalosporins. Preferable ester group as a protecting group during a chemical treatment can be e.g. mono- or dicyclic aralkyl, C₄ to C₁₀ -tertiary alkyl, C₁ to C₁₀ -β-haloalkyl or C₃ to C₈ -β-alkylsulfonylalkyl; and as a pharmacologically acceptable ester can be straight or branched chain C₃ to C₁₉ -alkanoyloxyalkyl, C₃ to C₆ -alkoxycarbonyloxyalkyl, C₄ to C₆ -tertiary alkyl, C₇ to C₉ -aralkyl or aryl esters. Preferable salt forming atom can be a light metal atom e.g. alkali metal or alkaline earth metal atom, especially sodium atom. Preferable salt forming group can be ammonium, C₁ to C₁₀ -primary to quaternary ammonium group or alkanoyloxy-alkaline earth metal group.

More specifically preferable compounds include those having C₁ to C₃ -alkyl as R; five-membered heterocyclic group having three to four hetero atoms selected from oxygen, nitrogen and sulfur and optionally substituted by C₁ to C₂ -alkyl as Het; and hydrogens as B¹ and B². Sodium, potassium and calcium salts, and C₂ to C₅ -alkanoyloxy-C₁ to C₃ -alkyl esters thereof are also another group of more preferable compounds.

Most preferable R is methyl or ethyl; Het is 1,3,4-thiadiazol-2-yl, 2-methyl-1,3,4-thiadiazol-5-yl or 1-methyltetrazol-5-yl; and B¹ and B² are hydrogens. The most preferable compounds can be in sodium salt or C₂ to C₅ -alkanoyloxy-C₁ or C₂ -alkyl ester forms thereof.

II. SYNTHESIS

The compounds of the formula (I) can be prepared by the following reactions:

(1) Acylation ##STR3## (wherein, R, Het, B¹ and B² are as defined above).

By this acylation, Malonic acid (III) or its reactive derivative is reacted with Methoxyamine compound (II) known from e.g. Japanese Published Patent Application No. 133,594/1974. Malonic acid compound (III) is used in the presence of a dehydrating condensing reagent e.g. dicyclohexylcarbodiimide or 1-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline. The reactive derivative of the Malonic acid compound (III) can be used in the presence of a reaction-promoting reagent e.g. a base. These are conventional methods well-known in the art of chemistry of β-lactam antibacterials. Especially preferable reactive derivatives are acid halogenides, acid anhydrides, and reactive esters. Preferable reaction-promoting reagents are aromatic bases and tertiary amines. The acylation is usually carried out at -20° C. to 60° C. in a conventional inert solvent. The product can be isolated by a conventional method.

(2) Deprotection of Carboxy-Protecting Group

When B¹ or B² is a carboxy-protecting group, this is deprotected to produce the corresponding carboxy compound (I) where said B¹ or B² is hydrogen. The method can be that specific to the protective group. Preferably, the method can also be that conventional in the chemistry of β-lactam antibacterials. Representatives are the hydrolysis of tertiary alkyl ester with a mineral acid; fission of an aralkyl ester with strong carboxylic acid or Lewis acid in the presence of anisole; hydrolysis with aqueous base; and the reductionof p-nitrobenzyl ester or haloalkyl ester; each operated under conventional conditions e.g. at -20° C. to 60° C. in an inert solvent, to isolate the product by usual method with good results.

(3) Formation of Salt

By the action of a base or exchange decomposition reaction of Compound (I) where B¹ or B² is hydrogen, the corresponding salt can be prepared. This may be done in an inert solvent at -20° C. to 60° C. If the solvent is suitably less polar, the objective salt usually precipitates. If required, a neutral salt solution may be lyophilized to obtain the product as powder.

(4) Esterification

By reacting a reactive derivative of alcohol with a salt of Compound (I) where B¹ or B² is hydrogen, or by reacting alcohol with activated carboxylic acid of Compound (I) in the form of e.g. acid halide, acid anhydride or reactive ester, the corresponding esteric Compound (I) can be prepared. The reaction can usually be carried out in an inert solvent at -20° C. to 60° C.

(5) Other Methods

In addition to above (1) to (4), Compound (I) can be prepared by the introduction of methoxy or Het-S group, or modification of substituent according to the manner conventional in the chemistry of β-lactam antibacterials.

These reactions may be done in a manner conventional in the chemistry of β-lactam antibacterials. If required, one or more of above procedures can be made in one and the same vessel, with or without removal of the reaction solvent used. The intermediates may be isolated or used without such isolation to the next reaction.

III. USAGE Antibacterial Use

The compounds (I) of this invention show stronger antibacterial activity against sensitive gram-positive and gram-negative bacteria and may be used for preventing or treating bacterial infections in human, veterinary or poultry field. For example, enteral or parenteral administration, especially intravenus or intramuscular or drip administration of the salt compounds prevents or cures bacterial infections caused by a sensitive bacteria in man at a daily dose of e.g. 0.5 to 2 g. In the case of topical administration, the dose can be much smaller.

Synthetic Use

For example, the Compound (I) having a protective group for chemical reactions are useful as intermediates for preparing antibacterial carboxylic acid by deprotection; free acids and its salts are interconvertible and also are useful starting material for each other to show another utility of this invention; and these are also useful for production of esters. As is exemplified above, the compounds are also useful as starting material for synthetic production.

IV. COMPOSITIONS

The compound (I) can be used in a wide variety of oral or parenteral dosage forms solely or in admixture with other coacting substances. The pharmaceutical compositions may be a mixture of 0.01 to 99% of Compound (I) with a pharmaceutical carrier which can be a solid material or liquid material in which the compounds are dissolved, dispersed or suspended. They can be in a unit dosage form. The solid compositions can take the form of tablets, powder, dry syrups, troches, granules, capsules, pills, suppositories or like solid preparations. The liquid compositions can take the forms of injections, ointments, dispersions, inhalant, suspensions, solution, emulsions, syrups or elixirs. They may be flavored, colored and tablets, granules and capsules may be coated.

V. METHOD OF USE

This invention also provides a method for treating or preventing human or veterinary bacterial infections by administering to the human or animal subject an effective amount of Compound (I) at a daily dose of e.g. 0.1 to 50 mg per kilogram body weight for injection or e.g. 1 to 100 mg milligram per kilogram body weight for oral administration, at an interval of e.g. 3 to 12 hours. For topical application, 1 to 100 μg may be applied.

The method is applicable for treating or preventing diseases caused by a sensitive strain of bacteria e.g. gram-positive Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis, Bacillus cereus, Diplococcus pneumoniae, Corynebacterium diphtheriae and gram-negative Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Shigella Sonnei, Salmonella paratyphi, Salmonella typhi, Serratia marsescens and Pseudomonas aeruginosa bacteria.

Representative diseases caused by above bacteria include pneumonia, bronchitis, pneumonitis, empyema, nasopharyngitis, tonsillitis, rhinitis, dermatitis, pustulosis, ulceration, abses, wound and soft tissue infections, ear infections, osteomyelitis, septicemia, gastroenteritis, enteritis, urinary tract infections and pyelonephritis.

VI. PRIOR ART

The prior art most closely related to this invention are U.S. Pat. Nos. 4,138,486, 4,201,782 and 4,226,866 disclosing 1-dethia-1-oxacephalosporins.

Following examples illustrate the embodiment of this invention.

When R is not hydrogen, the α-carbon of 7-malonamido side chain is an asymmetric carbon. D- and L-stereoisomers of Compound (I) can be produced by selecting suitable starting malonic acid (III) in a sterically pure form or separation of an isomeric mixture-product.

Followings are the abbreviations used in Examples. AOM is for acetoxymethyl. MeTdz is for 2-methyl-1,3,4-thiadiazol-5-yl. POM is for pivaloyloxymethyl. Ph is for phenyl. Tetr is for 1-methyl-5-tetrazolyl. Tdz is for 2-thiadiazolyl. ca. shows about.

Physical constants of the products and the structural change caused by the reaction indicated by an arrow mark accompanied with the yield in percent are shown at the suitable positions in the Tables given at the end of each Examples.

Amounts of the starting materials, reagents and solvents are expressed in the allowable ratio to the oxacephem starting material in each examples for obtaining good results.

EXAMPLE 1A Acylation in Tetrazolyl series (Het=Tetr) ##STR4##

To a solution of malonic acid half ester (1) (2.2 equivalents) in dichloromethane (9 weights) are added triethylamine (1 to 2 equivalents) and oxalyl chloride or phosphorus oxychloride (1 to 2 equivalents) with stirring at -25° C. under nitrogen atmosphere. The mixture is stirred at -10° to 10° C. for 1 to 3 hours. This is mixed with a suspension of methoxyamine (2) (1 equivalent, 1 weight) and pyridine (1.1 to 3 equivalents) in dichloromethane (10 to 30 weights). The mixture is stirred at -10° to 10° C. for 1 to 3 hours. The reaction mixture is diluted with benzene, washed with 2 N-hydrochloric acid, water, aqueous 5% sodium hydrogen carbonate and water, dried over magnesium sulfate and concentrated to dryness. The residue is chromatographed over silica gel containing 10% water, and the fraction eluted with benzene-ethyl acetate (7:1) mixture is concentrated to obtain diester (3).

By this method, the compounds of Table 1 can be obtained.

                                      TABLE 1                                      __________________________________________________________________________     Acylation in Tetrazolyl series (Het = Tetr)                                     ##STR5##                                                                                             diester (3)                                                                    yield                                                   No.                                                                               R        B.sup.1                                                                              B.sup.2                                                                             (%) shape                                                                               IR:ν .sub.max.sup.CHCl.sbsp.3cm.sup.-1                                              NMR: δ .sub.ppm.sup.CDCl.sbs                                             p.3(Hz value = J                       __________________________________________________________________________                                             value)                                 1  H        CHPh.sub.2                                                                           CHPh.sub.2                                                                          96  powder                                                                              3320, 1790,                                                                            3,47s3H, 3.48s2H, 3.75s3H,                                             1720.   4.23s2H, 4.55s2H, 5.00s1H,                                                     6.90s2H.                               2  CH.sub.3 CHPh.sub.2                                                                           CHPh.sub.2                                                                          99  powder                                                                              3300, 1792,                                                                            1.50d(7Hz)3H, 3.4brs1H,                                                1720.   (3.38s + 3.43s)3H, 3.75s3H, 4.23                                               s2H, 4.50s2H, 5.00s1H, 6.87s2H         3  C.sub.2 H.sub.5                                                                         CHPh.sub.2                                                                           CHPh.sub.2                                                                          quant                                                                              powder                                                                              3340, 1785,                                                                            0.87t(7Hz)3H, 1.97dq(8;8Hz)2H,                                         1718.   3.3brs1H, 3.36s3H, 3.73s3H,                                                    4.18s2H, 4.43s2H, 4.95s1H,                                                     6.83s2H.                               4  n-C.sub.3 H.sub.7                                                                       CHPh.sub.2                                                                           CHPh.sub.2                                                                          99  powder                                                                              3310, 1793,                                                                            0.6-2.3m7H, 3.40s3H, 3.47t                                             1720..  (6Hz)1H, 3.73s3H, (4.22s + 4.25                                                s)2H, 4.50s2H, 5.00s1H, 6.92                                                   s2H.                                   5  i-C.sub.3 H.sub.7                                                                       CHPh.sub.2                                                                           CHPh.sub.2                                                                          72  powder                                                                              3340, 1783,                                                                            0.92d(7Hz)3H, 1.03d(7Hz)3H,                                            1720.   2.4m1H, 3.16d(8Hz)1H, (3.32s                                                   + 3.43s)3H, 3.77s3H, (4.22s +                                                  4.30s)2H, (4.45s + 4.57s)2H,                                                   (4.93s + 4.98s)1H, 6.87s2H.            6  i-C.sub.4 H.sub.9                                                                       CHPh.sub.2                                                                           CHPh.sub.2                                                                          97  powder                                                                              3320, 1787,                                                                            1.03d(6Hz)6H, 1.83t(7Hz)2H,                                            1718.   1.9m1H, 3.38s3H, 3.50t(7Hz)                                                    1H, 3.70s3H, (4.16s + 4.21s)2H,                                                4.45s2H, 4.97s1H, 6.88s2H.             7  n-C.sub.6 H.sub.13                                                                      CHPh.sub.2                                                                           CHPh.sub.2                                                                          75  powder                                                                              --      0.6-2.2m13H, 3.37s3H, 3.43t                                                    (6Hz)1H, 3.68s3H, 4.18s2H,                                                     4.47s2H, 4.98s1H, 6.90s2H.             8  CH.sub.2 CHCH.sub.2                                                                     CHPh.sub.2                                                                           CHPh.sub.2                                                                          96  powder                                                                              3330, 1793,                                                                            2.70t(7Hz)2H, 3.40s3H, 3.50t                                           1720.   (7Hz)1H, 3.73s3H, 4.38s2H,                                                     4.48s2H, 4.97s1H, 4.7-5.2m2H,                                                  5.4-6.2m1H, 6.87s2H.                   9  CH.sub.2 CCH                                                                            CHPh.sub.2                                                                           CHPh.sub.2                                                                          97  powder                                                                              3400, 3300,                                                                            2.00s1H, 2.85brd(6Hz)2H,                                               1787, 1720.                                                                            (3.37s + 3.43s)3H, 3.63s3H,                                                    3.6brs1H, 4.18s2H, (4.40s +                                                    4.47s)2H, 4.98s1H, 6.90s2H.            10                                                                                 ##STR6##                                                                               CHPh.sub.2                                                                           CHPh.sub.2                                                                          quant                                                                              powder                                                                              3400, 1790, 1722.                                                                      1.97s3H, 2.3-2.7m4H, (3.38s +                                                  3.41s)3H, 3.75s3H, 3.7brs1H,                                                   4.23s2H, 4.50s2H, 6.83s2H.             11 C.sub.2 H.sub.5                                                                         t-C.sub.4 H.sub.9                                                                    CHPh.sub.2                                                                          82  powder                                                                              3300-3400,                                                                             0.97t(7Hz)3H, 1.48s9H, 1.93                                            1790, 1715.                                                                            dq(7;7Hz)2H, 3.13t(7Hz)1H,                                                     (3.50s + 3.57s)3H, 3.80s3H,                                                    4.27s2H, 4.60s2H, (5.00s +                                                     5.01s)1H, 6.88s1H.                     12 CH.sub.3 Si(CH.sub.3).sub.3                                                                   CHPh.sub.2                                                                          73  powder                                                                              3298, 1785,                                                                            (1.38d(8Hz) + 1.42d(8Hz))3H,                                           1724, 1637                                                                             3.53s3H, 3.65q(8Hz)1H, 3.87s                       H                   (Nujol).                                                                               3H, 4.27s2H, 4.63s2H, (5.07s                                                   5.10s)1H, 6.92s1H, 7.2-7.8m,                                                   8.20m1H(CD.sub.3 COCD.sub.3).          13 C.sub.2 H.sub.5                                                                         Si(CH.sub.3).sub.3                                                                   CHPh.sub.2                                                                          quant                                                                              powder                                                                              3200-3400,                                                                             0.97t(7Hz)3H, 1.97dq(7;7Hz)                                            1785, 1720,                                                                            2H, 3.33t(7Hz)1H, 3.53s3H,                         H                   1700sh. 3.75s3H, 4.20s2H, 4.57s2H,                                                     5.03s1H, 6.87s1H.                      __________________________________________________________________________

Compounds No. 12 and 13: an example of trimethylsilyl ester as B¹

To a solution of 2-ethylmalonic acid bis-trimethylsilyl ester (1) (1.8 equivalents) in benzene (10 weights) are added N,N-dimethylformamide (0.1 equivalent) and thionyl chloride (1.5 equivalents) at room temperature. The mixture is stirred for 2.5 hours and concentrated under reduced pressure to give half ester chloride. This is dissolved in dichloromethane (4 weights), and added to a mixture of methoxyamine (2) (1 equivalent, 1 weight), pyridine (1.2 equivalents) and dichloromethane (20 weights) under ice cooling, and the mixture is worked up by the conventional method as given above to afford carboxylic acid Compound No. 12 or 13 (3, B¹ =H) due to hydrolysis of the trimethylsilyl group.

EXAMPLE 1B Acylation in Thiadiazolyl series (Het=Tdz) ##STR7##

A mixture of methoxyamine (4) (1 equivalent, 1 weight) and pyridine (2 to 3 equivalents) in dichloromethane (10˜20 weights) are portionwise mixed under nitrogen with a cooled solution of malonic acid half ester (1) (1 to 1.5 equivalent), pyridine (2 to 3 equivalents) and phosphorus oxychloride (1 to 1.5 equivalents) in dichloromethane prepared at 0° C. for 30 minutes. The resulting mixture is kept at -40° C. with stirring during the addition, and 0° C. for 30 minutes for the reaction under nitrogen. The reaction mixture is diluted with ethyl acetate, washed with 2 N-hydrochloric acid, water, aqueous 5% sodium hydrogen carbonate and water, dried over magnesium sulfate and concentrated to dryness. The residue is chromatographed over silica gel containing 10% water. The fraction eluted with a mixture of benzene and ethyl acetate (5:1) affords diester (5) by concentration.

Compounds of Table 2 are prepared by this method.

                                      TABLE 2                                      __________________________________________________________________________     Acylation in Thiadiazolyl series (Het = Tdz)                                    ##STR8##                                                                                           diester (3)                                                                    yield                                                     No.                                                                               R      B.sup.1                                                                              B.sup.2                                                                             (%) shape                                                                               IR:ν .sub.max.sup.CHCl.sbsp.3cm.sup.-1                                              NMR: δ .sub.ppm.sup.CDCl.sbsp.                                           3(Hz value = J value)                    __________________________________________________________________________     1  CH.sub. 3                                                                             CHPh.sub.2                                                                           CHPh.sub.2                                                                          74  powder                                                                              3350, 1784,                                                                            1.49d(7Hz)3H, (3.35s + 3.40s)                                          1720.   3H, 3.51q(7Hz)1H, 4.2-4.7m4H,                                                  4.99s1H, 6.88s1H, 6.92s1H,                                                     8.87s1H.                                 2  C.sub.2 H.sub.5                                                                       CHPh.sub.2                                                                           CHPh.sub.2                                                                          75  powder                                                                              3350, 1785,                                                                            0.90t(7Hz)3H, 1.97dq(7;7Hz)                                            1720.   2H, 3.40t(7Hz)1H, 3.43s3H,                                                     4.2-4.6m4H, 4.99s1H, 6.90s1H,                                                  6.93s1H, 8.83s1H.                        3  n-C.sub.3 H.sub.7                                                                     CHPh.sub.2                                                                           CHPh.sub.2                                                                          76  powder                                                                              3400-3300,                                                                             0.7-2.1m7H, 3.40s3H, 3.41t                                             1785, 1718.                                                                            (3Hz)1H, (4.33s + 4.46s)2H,                                                    4.50s2H, 5.01s1H, 6.93s1H,                                                     6.94s1H, 8.90s1H.                        4  n-C.sub.4 H.sub.9                                                                     CHPh.sub.2                                                                           CHPh.sub.2                                                                          70  powder                                                                              3300-3400,                                                                             0.6-2.3m9H, 3.40s3H, 3.50t                                             1785, 1718.                                                                            (6Hz)1H, 4.1-4.8m4H, 4.99s1H,                                                  6.83s1H, 8.80s1H.                            ##STR9##                                                                             CHPh.sub.2                                                                           CHPh.sub.2                                                                          70  powder                                                                              3345, 1785, 1720.                                                                      2.72t(7Hz)2H, 3.40s3H, 3.4 brs1H,                                              4.1-4.7m4H, 4.8-5.3m 2H, 4.98s1H,                                              5.4-6.1m1H, 6.88s1H, 6.93s1H,                                                  8.82s1H.                                 6  C.sub.2 H.sub.5                                                                       Si(CH.sub.3).sub.3                                                                   CHPh.sub.2                                                                          80  powder                                                                              ca3300, 0.97t(7Hz)3H, 2.03dq(7;7Hz)                                            1785, 1715.                                                                            2H, 3.37t(7Hz)1H, (4.30d +                         H                           4.47d)ABq(10Hz)2H, 4.60s2H,                                                    5.08s1H, 6.91s1H, 7.93brs1H,                                                   8.98s1H.                                 __________________________________________________________________________

EXAMPLE 1C Acylation in Methylthiadiazolyl series (Het=MeTdz) ##STR10##

To a solution of methoxyamine (1 weight, 1 equivalent) in dichloromethane (10 to 20 weights) cooled at -22° to -40° C. are added ethylmalonic acid monobenzhydryl ester (1 to 1.5 equivalents) pyridine (4 to 6 equivalents) and phosphorus oxychloride (1 to 2 equivalents). The mixture is stirred at 0° C. for 1 to 2 hours. The reaction mixture is concentrated under reduced pressure. The obtained residue is dissolved in ethyl acetate, washed with diluted hydrochloric acid, water, aqueous diluted sodium hydrogen carbonate and water, dried over magnesium sulfate and evaporated to remove the solvent. The residue is purified by chromatography over silica gel containing 10% water to give objective product (3) from the fraction eluted with benzene and ethyl acetate (7:1) mixture.

R=C₂ H₅, B¹ =--CHPh₂, B² =--CHPh₂ :

IR: ν_(max) ^(CHCl).sbsp.3 3400, 1780, 1718.

NMR: δ_(ppm) ^(CDCl).sbsp.3 0.92t(7 Hz)3H, 2.00dq(7;7 Hz)2H, 2.67s3H, 3.37t (7 Hz)1H, 3.40s3H, (4.20d(12 Hz)1H+4.50d)ABq(12 Hz)2H, 4.47s2H, 5.00s1H, 6.92s2H, 7.50brs1H.

EXAMPLE 2A Deesterification in Tetrazolyl series (Het=Tetr)

with CF₃ COOH

To an ice-cold solution of ester (3) (1 weight) in dichloromethane (3 to 10 weights) are added anisole (1 to 3 weights) and trifluoroacetic acid (1 to 2 weights). The mixture is stirred for 1 hour, diluted with benzene, and concentrated in vacuo under reduced pressure. The residue is triturated in a mixture of ether and petroleum ether to pulverize the product, filtered to collect it and washed with the same solvent to give dicarboxylic acid or its monoester (6).

with AlCl₃

To a solution of diester (3) (1 weight) in a mixture of dichloromethane (5 to 10 weights) and anisole (3 to 10 weights) is added aluminum chloride (1 to 3 weights) at -20° C. The mixture is stirred at the same temperature for 1 hour. The reaction mixture is diluted with n-hexane to separate precipitate thus formed. This is collected by filtration. The filtrate is extracted with aqueous 5% sodium hydrogen carbonate. The extract is combined with above precipitate and washed with ether. The mixture is acidified with 2 N-hydrochloric acid, saturated with sodium chloride and extracted with methyl ethyl ketone. The extract is dried over magnesium fulfate and concentrated to dryness giving carboxylic acid (7).

Compounds of Table 3 are prepared by this method.

                                      TABLE 3                                      __________________________________________________________________________     Deesterification in Tetrazolyl series (Het = Tetr)                                                            carboxylic acid product (6)                     No.                                                                               R         B.sup.1  B.sup.2  shape                                                                               IR: ν .sub.max.sup.KBrcm.sup.-1                                                    NMR: δ .sub.ppm.sup.CD.sb                                                sp.3.sup.COCD.sbsp.3(Hz value                                                  = J value)                          __________________________________________________________________________     1  H         CHPh.sub.2                                                                               CHPh.sub.2                                                                             powder                                                                              3350br,                                                                               3.50s5H, 3.98s3H, 4.32s2H,                            quant             1788, 1707.                                                                           4.63s2H, 5.07s1H.                                H         H                                                       2  CH.sub.2  CHPh.sub.2                                                                               CHPh.sub.2                                                                             powder                                                                              3292br,                                                                               (1.32d(7Hz) + 1.36d(7Hz))3H,                                                   3.48                                                  quant             1785, 1720.                                                                           s3H, 3.5brs1H, 3.98s3H,                                                        4.32s2H,                                         H         H                   4.63s2H, 5.06s1H.                   3  CH.sub.3  AOM      CHPh.sub.2    3250, 1755,                                                                           1.38m3H, 2.07s3H, 3.52s2H,                                                     4.00                                                                    1765, 1690,                                                                           s3H, 4.50m2H, 4.65brs2H,                                                       5.08s                                                     H 99%         1680, 1640,                                                                           1H, 5.78s2H.                                                            1605(Nujol).                                                     Na                                                       4  CH.sub.3  POM      CHPh.sub.2                                                                              powder                                                                              3250, 1760,                                                                           1.17s9H, 1.35br3H, 3.48s3H,                                                    3.93                                                                    1685, 1605.                                                                           s3H, 4.50m4H, 5.02s1H,                                                         5.75s2H.                                                  H 94%         (Nujol)                                                          Na                                                       5  C.sub.2 H.sub.5                                                                          CHPh.sub.2                                                                               CHPh.sub.2                                                                             powder                                                                              3250br,                                                                               0.95t(7Hz)3H,                                                                  1.90dq(7;7Hz)2H,                                      85%               1780, 1715.                                                                           3.48s3H, 3.5brs1H, 3.97s3H,                      H         H                   4.31s2H, 4.63s2H, 5.07s1H.          6  C.sub.2 H.sub.5 (isomer A)                                                               CHPh.sub.2   H                                                                       59%                                                                                ##STR11##                                                                              powder                                                                              3350, 1789, 1740, 1700sh.                                                             0.93t(7Hz)3H, 1.88dq(7;7Hz)2H,                                                 .40s3H, 3.4brs1H, 4.00s3H,                                                     4.37s2H, 4.71s2H, (5.03s +                                                     5.05 s)1H, 7.60s1H,                                                            7.7-8.1m4H.                         7  C.sub.2 H.sub.5 (isomer B)                                                               CHPh.sub.2   H                                                                       75%                                                                                ##STR12##                                                                              powder                                                                              3350, 1788, 1740, 1690sh.                                                             0.93t(7Hz)3H, 1.88dq(7;7Hz)2H,                                                 .37s3H, 3.4brs1H, 3.97s3H,                                                     (4.27s + 4.48s)2H, 4.70s2H,                                                    (5.00s + 5.03s)1H, 7.65s1H,                                                    7.7-8.2m4H.                         8  C.sub.2 H.sub.5                                                                          t-C.sub.4 H.sub.9   H                                                                86%                                                                                ##STR13##                                                                              powder                                                                              1790, 1750, 1710sh (CHCl.sub.3).                                                      0.7-2.7m24H, 3.33t(7Hz)1H,                                                     3.47s3H, 3.92s3H, 4.25s2H,                                                     4.60 s2H, 5.03s1H, 5.90s2H                                                     (CDCl.sub.3).                       9  C.sub.2 H.sub.5                                                                          t-C.sub.4 H.sub.9                                                                       CHPh.sub.2                                                                              powder                                                                              3300, 1780,                                                                           1.13t(7Hz)3H, 1.45s9H, 1.93dq                               93%         1730sh, 1705,                                                                         (7;7Hz)2H, 3.17t(7Hz)1H,                                                       3.53s                                                     H             (CHCl.sub.3).                                                                         3H, 3.90s3H, 4.30s2H,                                                          4.62s2H,                                                                       5.07s1H (CDCl.sub.3).               10 C.sub.2 H.sub.5                                                                          Ph       CHPh.sub.2    3320, 1785,                                                                           1.00t(7Hz)3H,                                                                  2.00dq(7;7Hz)2H,                                            78%         1765, 1705sh.                                                                         3.52s3H, 3.80t(7Hz)1H, (3.95s                                                  +                                                         H                    3.98s)3H, 4.27s2H, (4.60s +                                                    4.65s)2H, 5.12s1H,                                                             7.0-7.7m5H.                         11 C.sub.2 H.sub.5                                                                          AOM      CHPh.sub.2                                                                              powder      0.98t(7Hz)3H,                                                                  1.93dq(7;7Hz)2H,                                            quant              2.10s3H, 3.45t(7Hz)1H,                                                         3.57s3H,                                                  H                    4.02s3H, 4.33s2H, 4.63s2H,                                                     5.08                                                                           s1H, 5.78s2H (CDCl.sub.3 +                                                     CD.sub.3 OD).                       12 C.sub.2 H.sub.5                                                                          POM      CHPh.sub.2                                                                              powder      0.95t(7Hz)3H, 1.16s9H, 1.89dq                               48%                (7;7Hz)2H, 3.5brs1H, 3.45s3H,                             H                    3.94s3H, 4.28s2H, 4.61s2H,                                                     5.04                                                                           s1H, 5.71s2H.                       13 i-C.sub.3 H.sub.7                                                                        CHPh.sub.2                                                                               CHPh.sub.2                                                                             powder                                                                              3300, 1784,                                                                           1.00d(8Hz)3H, 1.02d(8Hz)3H,                                                    2.4                                                   88%               1723.  m1H, (3.20d(8Hz)                                                               + 3.25(8Hz))1H,                                  H         H                   3.47s3H, 4.00s3H, 4.35s2H,                                                     4.67                                                                           s2H, 5.10s1H.                       14 i-C.sub.4 H.sub.9                                                                        CHPh.sub.2                                                                               CHPh.sub.2                                                                             powder                                                                              3300br, 1785,                                                                         0.6- 2.2m9H, 3.50t(7Hz)1H,                                                     3.50                                                  88%               1721.  s3H, 4.00s3H, 4.40s2H, 4.65s                     H         H                   2H, 5.10s1H.                        15 n-C.sub.6 H.sub.13                                                                       CHPh.sub.2                                                                               CHPh.sub.2                                                                             powder                                                                              3250br, 1785,                                                                         0.7-2.2m13H, 3.47s3H,                                                          3.5brs1H,                                             92%   94%         1720.  3.97s3H, 4.35s2H, 4.68s2H,                       H         H                   5.11s1H.                            16 CH.sub.2 CHCH.sub.2                                                                      CHPh.sub.2                                                                               CHPh.sub.2                                                                             powder                                                                              3305br, 1785,                                                                         2.63t(7Hz)2H, 3.48s3H, 3.55t                          84%               1720.  (8Hz)1H, 4.00s3H, 4.33s2H,                       H         H                   4.65s2H, 4.8-5.3m2H, 5.08s1H,                                                  5.6-6.3m1H.                         17 CH.sub.2 CCH                                                                             CHPh.sub.2                                                                               CHPh.sub.2                                                                             powder                                                                              3280, 1785,                                                                           2.05s1H, [2.70d(7Hz) +                                                         2.74d(7Hz)]                                           quant                                                                                            1722, 1685sh.                                                                         2H, 3.50s3H, 3.75t(7Hz)1H,                       H         H                   3.98s3H, 4.30s2H, 4.61s2H,                                                     5.07s1H.                            18                                                                                 ##STR14##                                                                               CHPh.sub.2   H                                                                       68%                                                                                CHPh.sub.2    H                                                                        powder                                                                              3300, 1780, 1720, 1685sh.                                                             2.05s3H, 2.2-2.7m4H, 3.50s3H,                                                  3.7brs1H, 3.98s3H, 4.33s2H,                                                    4.65s2H, (5.05s + 5.08s)1H.         19 n-C.sub.3 H.sub.7                                                                        CHPh.sub.2                                                                               CHPh.sub.2                                                                             powder                                                                              3285br, 1785,                                                                         0.7-2.1m7H, 3.49s3H, 3.5brs1H,                                                 -    88%    1721. 3.98s3H,                                                     4.32s2H, 4.63s2H,                                H         H                   5.05s1H.                            __________________________________________________________________________

EXAMPLE 2B Deesterification in Thiadiazolyl series (Het=Tdz)

with AlCl₃

To a solution of diester (5) (1 weight) in a mixture of dichloromethane (5 to 10 weights) and anisole (3 to 10 weights) is added aluminum chloride (1 to 3 weights) at -20° C. The mixture is stirred at the same temperature for 1 hour. The reaction mixture is diluted with n-hexane to separate precipitate. This is collected by filtration. The filtrate is extracted with aqueous 5% sodium hydrogen carbonate. The extract is combined with above precipitate and washed with ether. The mixture is acidified with 2 N-hydrochloric acid, saturated with sodium chloride and extracted with methyl ethyl ketone. The extract is dried over magnesium sulfate and concentrated to dryness giving carboxylic acid (7).

with CF₃ COOH

To a solution of the starting diester (5) (1 weight) in a mixture of dichloromethane (2 to 4 weights) and anisole (2 to 3 weights) is added trifluoroacetic acid (2 to 4 weights) and stirred for 1 to 3 hours. After concentration in vacuo, the reaction product is washed with petroleum ether to give objective carboxylic acid (7).

Compounds of Table 4 are prepared by these methods.

                                      TABLE 4                                      __________________________________________________________________________     Deesterification in Thiadiazolyl series (Het = Tdz)                                                          carboxylic acid product (7)                      No. R         B.sup.1  B.sup.2                                                                               shape                                                                               IR: ν.sup.KBr .sub.max                                                              NMR: δ .sub.ppm.sup.CD.sb                                                sp.3.sup.COCD.sbsp.3(Hz value                                                  = J value)                          __________________________________________________________________________     1   --CH.sub.3                                                                               --CHPh.sub.2                                                                             --CHPh.sub.2                                                                         powder                                                                              ca3300, 1782,                                                                          (1.33d(7Hz) + 1.37d(7Hz))3H,                            88%            1740.   3.48s3H, 3.6brs1H, (4.45s +                                                    4.50                                              --H       --H                s)2H, 4.63s2H, 5.08s1H,                                                        9.42s1H.                            2   --C.sub.2 H.sub.5                                                                        --CHPh.sub.2                                                                             --CHPh.sub.2                                                                         powder                                                                              ca3300, 1784,                                                                          0.93t(7Hz)3H,                                                                  1.90dq(7;7Hz)2H,                                        90%            1720.   3.5brs1H, 3.48s3H, (4.44s +                                                    4.49                                              --H       --H                s)2H, 4.63s2H, 5.08s1H,                                                        9.40s1H                             3   --C.sub.2 H.sub.5                                                                        --POM    --CHPh.sub.2                                                                          powder       0.96t(7Hz)2H, 1.21s9H, 1.90dq                                 quant            (7;7Hz)2H, 3.50t(7Hz)1H,                                                       3.52s                                                      --H                 3H, (4.40d + 4.60d)                                                            ABq(14Hz)2H,                                                                   4.68s2H, 5.12s1H, 5.80s2H,                                                     8.21                                                                           d(8Hz)1H, 9.40s1H.                  4   --n-C.sub.3 H.sub.7                                                                      --CHPh.sub.2                                                                             --CHPh.sub.2                                                                         powder                                                                              ca3300, 1785,                                                                          0.7-2.1m7H, 3.48s3H,                                                           3.5brs1H,                                               88%            1740.   (4.45s + 4.50s)2H, 4.63s2H,                       --H       --H                5.08s1H, 9.40s1H.                   5   --n-C.sub. 4 H.sub.9                                                                     --CHPh.sub.2                                                                             --CHPh.sub.2                                                                         powder       0.7-2.2m9H, 3.48s3H,                                                           3.5brs1H,                                               95%                    (4.43s + 4.48s)2H, 4.65s2H,                       --H       --H                5.12s1H, 9.40s1H.                   6   --CH.sub.2 CH═CH.sub.2                                                               --CHPh.sub.2                                                                             --CHPh.sub.2                                                                         powder                                                                              3250, 1782,                                                                            2.62t(7Hz)2H, 3.47s3H, 3.47t                            57%            1720.   (7Hz)1H, (4.33s + 4.48s)2H,                       --H       --H                4.63s2H, 4.8-5.3m2H, 5.09s1H,                                                  5.5-6.3m1H, 9.42s1H.                __________________________________________________________________________

EXAMPLE 2C Deesterification in Methylthiadiazolyl series (Het=MeTdz)

To a solution of ester (1 weight) in a mixture of dichloromethane (10 weights) and anisole (5 to 10 weights) cooled at -20° C. to 0° C. is added aluminum chloride (1 to 1.5 weights). After keeping at the same temperature for 1 to 2 hours, the reaction mixture is shaken with a mixture of ethyl acetate and diluted hydrochloric acid. Separated organic layer is washed with water, evaporated to remove the solvent and triturated with hexane to give the objective product as powder.

R=-C₂ H₅, B¹ =-CHPh₂ →H, B² =-CHPh₂ →H: Yield=29%.

IR: ν_(max) ^(KBr) 1780, 1710, 1630 cm⁻¹.

NMR: δ_(ppm) ^(CD).sbsp.3^(COCD).sbsp.3 0.95t(7 Hz)3H, 2.03dq(7;7 Hz)2H, 2.73s3H, 3.48t(7 Hz)1H, 3.52s3H, (4.33d+4.52d)ABq(14 Hz)2H, 4.67s2H, 5.13s1H, 8.5brs1H.

EXAMPLE 3A Esterification in Tetrazolyl series (Het=Tetr)

To an ice cold solution of carboxylic acid (6) (1 equivalent, 1 weight) in acetone (2 to 4 weights) is added 1.8 M/L-sodium 2-ethylhexanoate (1 to 2 equivalents), and the mixture is stirred for 30 minutes. The reaction mixture is diluted with ether, and separated salt is collected by filtration.

When the esterifying reagent is chloride or bromide, the salt is dissolved in acetone (4 to 10 weights), mixed with the esterifying reagent (1 to 2 equivalents) and sodium iodide (1 to 2 equivalents) in acetone (2 to 3 weights) and stirred for 1 to 2 hours. When the esterifying reagent is bromide or iodide, the salt is dissolved in N,N-dimethylformamide or N,N-dimethylacetamide (4 to 5 weights), mixed with the esterifying reagent (1 to 2 equivalents) in the same solvent (1 to 3 weights) and stirred for 0.5 to 2 hours.

The mixture is diluted with ethyl acetate, washed with water, dried over sodium sulfate and concentrated in vacuo. The residue is purified by chromatography over silica gel containing 10% water to afford desired ester (8).

By using one of these methods, the compounds of Table 5 are prepared.

                                      TABLE 5                                      __________________________________________________________________________     Esterification in Tetrazolyl series (Het = Tetr)                                                            ester product (8)                                 No.                                                                               R       B.sup.1  B.sup.2  shape                                                                               IR: ν .sub.max.sup.CHCl.sbsp.3cm.sup.                                       -1        NMR: δ .sub.ppm.sup.CDCl                                                 .sbsp.3(Hz value = J               __________________________________________________________________________                                                 value)                             1  CH.sub.3                                                                               H        CHPh.sub.2                                                                              powder         1.47d(8Hz)3H, 2.07s3H, 3.48                   87%                              q(8Hz)1H, 3.55s3H, 3.78s3H,                   Na                               4.25s2H, 4.62s2H, 5.03s1H,                    70%                              5.75s2H, 6.88s1H,                                                              7.08-7.67m.                                   AOM                                                                 2  CH.sub.3                                                                               Na        Na      powder                                                                              3415, 3360,                                                                              1.47d(8Hz)3H, 2.10s3H, 2.15s                  35%                    1790, 1770,                                                                              3H, 3.45q(8Hz)1H, 3.52s3H,                    AOM       AOM          1745, 1711,                                                                              3.92s3H, 4.27brs2H, 4.62s2H,                                         1632.     5.03s1H, 5.77s2H, (5.83d +                                                     5.98d)ABq(6Hz)2H.                  3  CH.sub.3                                                                               AOM      CHPh.sub.2                                                                              powder                                                                              3415, 3360,                                                                              1.23s9H, 1.47d(8Hz)3H, 2.10s                           H  99%        1792, 1756,                                                                              3H, 3.47q(8Hz)1H, 3.52s3H,                             Na             1715, 1633.                                                                             3.90s3H, 4.28s2H, 4.63s2H,                                 23%                 5.03s1H, 5.77s2H, (5.85d +                             POM                     6.02d)ABq(6Hz)1H.                  4  CH.sub.3                                                                               H        CHPh.sub.2                                                                              powder         1.18s9H, 1.47d(8Hz)3H, 3.45q                  87%                              (8Hz)1H, 3.55s3H, 3.78s3H,                    Na                               4.27s2H, 4.62s2H, 5.05s1H,                    82%                              5.78s2H, 6.88s1H, 7.15-7.68m                  POM                                                                 5  CH.sub.3                                                                               POM      CHPh.sub.2                                                                              powder                                                                              3420, 3345,                                                                              1.20s9H, 1.47d(8Hz)3H, 2.15s                           H  94%        1791, 1756,                                                                              3H, 3.43q(8Hz)1H, 3.52s3H,                             Na            1712, 1633.                                                                              3.90s3H, 4.27brs2H, 4.60s2H,                               29%                 5.03s1H, 5.77s2H, (5.83d +                             AOM                     5.98d)ABq(6Hz)1H.                  6  CH.sub.3                                                                               H         H       powder                                                                              3400, 1791,                                                                              1.20s9H, 1.23s9H, 1.47d(7Hz)                  72%                    1752, 1710sh,                                                                            3H, 3.43q(7Hz)1H, 3.52s3H,                    Na        Na           1632.     3.90s3H, 4.27s2H, 4.62s2H,                    47%                              5.03s1H, 5.77s2H, (5.85d +                    POM       POM                    6.00d)ABq(6Hz)2H.                  7  C.sub.2 H.sub.5                                                                        H        CHPh.sub.2                                                                              powder                                                                              3300, 1785,                                                                              1.03t(7Hz)3H,                                                                  2.08dq(7;7Hz)2H,                               80%                   1710.     3.50s3H, 3.5brs1H, 3.66s3H,                                                    4.15                                          Ph                               s2H, 4.53s2H, 5.03s1H,                                                         6.83s1H.                           8  C.sub.2 H.sub.5                                                                        t-C.sub. 4 H.sub.9                                                                       ##STR15##    3400, 1792, 1745, 1712.                                                                  0.6-2.7m24H, 1.45s9H,                                                          3.15t(7Hz) 1H, 3.53s3H,                                                        3.92s3H, 4.30s2H, 4.63s2H,                                                     5.05s1H, 5.83d(5Hz)1H,                                                         5.98d(5Hz)1H.                      9  C.sub.2 H.sub.5 (isomer A)                                                             t-CH.sub. 4 H.sub.9                                                                      ##STR16##                                                                              powder                                                                              3300, 1790, 1738, 1710.                                                                  0.90t(7Hz)3H, 1.43s9H, 1.87dq                                                  7;7Hz)2H, 3.10t(7Hz)1H, 3.43s                                                  H, 3.92s3H, 4.30s2H, 4.70s2H,                                                  .02s1H, 7.40s1H, 7.5-8.0m4H.       10 C.sub.2 H.sub.5 (isomer B)                                                             t-C.sub. 4 H.sub.9                                                                       ##STR17##                                                                              powder                                                                              3300, 1790, 1736, 1710.                                                                  0.90t(7Hz)3H, 1.44s9H,                                                         1.87dq(7; 7Hz)2H,                                                              3.11t(7Hz)1H, 3.45s3H,                                                         3.91s3H, (4.17s + 4.40s)2H,                                                    4.63s 1H, 5.05s1H, 7.47s1H,                                                    7.5-8.0m4H                         11 C.sub.2 H.sub.5                                                                        H        CHPh.sub.2                                                                              powder         0.97t(7Hz)3H, 1.23s9H,                                                         1.97dq                                        81%                              (7;7Hz)2H, 3.28t(7Hz)1H,                                                       (3.52                                         Na                               s + 3.55s)3H, 3.58s3H,                                                         4.23s2H,                                      82%                              4.58s2H, 5.02s1H, (5.68d +                                                     5.81d)                                        POM                              ABq(6Hz)2H, 6.87s1H.               12 C.sub.2 H.sub.5                                                                        POM      H        powder                                                                              3350, 1790,                                                                              0.97t(7Hz)3H, 1.20s9H,                                                         1.98dq                                                     quant     1755, 1705.                                                                              (7;7Hz)2H, 2.15s3H,                                                            3.28t(7Hz)                                             Na                      1H, (3.50s + 3.52s)3H,                                                         3.90s3H,                                                   70%                 (4.21d + 4.38d)ABq(12Hz)2H,                                                    4.60                                                   AOM                     s2H, 5.03s1H, (5.73d +                                                         5.83d)ABq                                                                      (6Hz)2H, 7.48d(4Hz)1H.             13 C.sub.2 H.sub.5                                                                        H         H       powder                                                                              3350, 1792,                                                                              0.98t(7Hz)3H, 1.30s9H,                                                         1.40s9H,                                      quant                  1755, 1702.                                                                              1.98dq(7;7Hz)2H,                                                               3.28t(7Hz)1H,                                 Na        Na                     (3.50s +  3.52s)3H, 3.91s3H,                                                   4.27                                          44%                              s2H, 4.60s2H, 5.03s1H, (5.73d                                                  +                                             POM       POM                    5.83d)ABq(6Hz)2H, (5.84d +                                                     6.00d)                                                                         ABq(6Hz)1H, 7.47d(4Hz)1H.          14 C.sub.2 H.sub.5                                                                        H        CHPh.sub.2                                                                              powder         0.96t(7Hz)3H,                                                                  1.98dq(7;7Hz)2H,                              81%                              2.03s3H, 3.35t(7Hz)1H, 3.53s                                                   +                                             Na                               3.55s)3H, 3.73s3H, 4.23s2H,                   51%                              4.61s2H, 5.05s1H, 5.73s2H,                    AOM                              6.90s1H.                           15 C.sub.2 H.sub.5                                                                        H         H       powder                                                                              3350, 1790,                                                                              0.96t(7Hz)3H,                                                                  1.95dq(7;7Hz)2H,                              quant                  1770, 1740,                                                                              2.08s3H, 2.15s3H,                                                              3.32t(7Hz)1H,                                 Na        Na           1700sh.   3.53s3H, 3.96s3H, (4.23d +                                                     4.40d)                                        11%                              ABq(14Hz)2H, 4.63s2H,                                                          5.05s1H,                                      AOM       AOM                    5.75s2H, (5.85d                                                                + 5.97d)ABq(5Hz)2H                 16 C.sub.2 H.sub.5                                                                        AOM      H        powder                                                                              3350, 1792,                                                                              0.98t(7Hz)3H, 1.24s9H,                                                         2.00dq                                                     96%       1755, 1710.                                                                              (7;7Hz)2H, 2.12s2H,                                                            3.28t(7Hz)                                             Na                      1H, (3.50s + 3.51s)3H,                                                         3.88s3H,                                                   32%                 4.25s2H, 4.58s2H, 5.00s1H,                             POM                     5.73s2H, (5.83d                                                                + 5.97d)ABq(5Hz)                                                               2H, 7.3brs1H.                      __________________________________________________________________________

Esterification through acid chloride to give the compound No. 7 in Table 5

By the action of pyridine (1.5 equivalents) and oxalyl chloride (1.2 equivalents) to a solution of 7β-(2-ethyl-2-carboxyacetamido)-7α-methoxy-3-(1-methyl-5-tetrazolyl)-thiomethyl-1-oxa-1-dethia-3-cephem-4-carboxylic acid diphenylmethyl ester (1 equivalent) in dichloromethane (11 weights) at 0° C. for 1 hour, acid chloride is prepared. To this solution is added phenol (2 equivalents) and pyridine (1.5 equivalents), and stirring continued for 30 minutes. The reaction mixture is diluted with ethyl acetate, washed with 2 N-hydrochloric acid and water, dried over magnesium sulfate and concentrated. The residue is chromatographed over silica gel containing 10% water (34 weights). The fraction eluted with a mixture of benzene and ethyl acetate (10:1) affords 7β-(2-ethyl-2-phenoxycarbonylacetamido)-7α-methoxy-3-(1-methyl-5-tetrazolyl)thiomethyl-1-oxa-1-dethia-3-cephem-4-carboxylic acid diphenylmethyl ester (0.8 equivalents).

EXAMPLE 3B Esterification in Thiadiazolyl series (Het=Tdz)

To an ice cooled solution of a sodium salt (1 equivalent, 1 weight) in N,N-dimethylformamide or N,N-dimethylacetatamide (4 to 8 weight) is added pivaloyloxymethyl iodide (2 to 4 equivalents). The mixture is stirred for 1 to 2 hours. About 30 minutes after addition of a small amount of thiourea for decomposing the remaining iodide reagent, the reaction mixture is poured onto water and extracted with ethyl acetate. The extract is washed with water, dried over magnesium sulfate, and concentrated under reduced pressure. The residue is purified by chromatography over silica gel. The fraction eluted with a mixture of benzene and ethyl acetate (2:1) affords powder of ester (9) after lyophilization.

A method similar to that of Example 3A can also be applied.

Thus, compounds of Table 6 are prepared by the methods given above.

                                      TABLE 6                                      __________________________________________________________________________     Esterification in Thiadiazolyl series (Het = Tdz)                                                 ester product (9)                                           No.                                                                               R   B.sup.1                                                                              B.sup.2                                                                               shape                                                                               IR: ν .sub.max.sup.CHCl.sbsp.3cm.sup.-1                                              NMR: δ .sub.ppm.sup.CDCl.sbsp.3(Hz                                        value = J value)                            __________________________________________________________________________                                       1.20s9H, 1.23s9H, 1.45d(7Hz)3H,                     --Na   --Na      3415, 1791,                                                                              3.50q(8Hz)1H, 3.53s3H, (4.25d +              1  --CH.sub.3                                                                          47%         powder        4.63d)ABq(14Hz)2H, 4.65s2H,                         --POM  --POM     1753, 1711.                                                                              5.08s1H, 5.80s2H, (5.93d + 6.05d)                                              ABq(6Hz)2H, 9.08s1H.                                --H                        0.98t(7Hz)3H, 1.19s9H, 2.00dq                        quant           3350, 1788,                                                                              (7;7Hz)2H, 3.31t(7Hz)1H, (3.52s              2  --C.sub.2 H.sub.5                                                                  --Na  --CHPh.sub.2                                                                          powder        + 3.55s)3H, (4.27d + 4.50d)ABq(14                    46%             1750, 1720.                                                                              Hz)1H, 4.59s2H, 5.04s1H, (5.73d                     --POM                      + 5.83d)ABq(5Hz)2H, 7.60s1H,                                                   8.98s1H.                                                                       0.97t(7Hz)3H, 1.19s9H, 1.98dq                             --H                  (7;7Hz)2H, 2.14s3H, 3.28t(7Hz)                                       3350, 1790,                                                                              1H, (3.49s + 3.51s)3H, (4.23d +              3  --C.sub.2 H.sub.5                                                                  --POM --Na  32%                                                                             powder        4.60d)ABq(14Hz)2H, 4.60s2H,                                          1755, 1705.                                                                              5.02s1H, (5.73d + 5.83d)ABq(6Hz)                          --AOM                2H, (5.87d + 5.98d)ABq(6Hz)2H,                                                 7.5brs1H, 9.07s1H.                                  --H   --H                  0.97t(7Hz)3H, 1.19s9H, 1.23s9H                       quant           3350, 1790,                                                                              1.98dq(7;7Hz)2H, 3.27t(7Hz)1H,               4  --C.sub.2 H.sub.5                                                                  --Na  --Na   powder        (3.48s + 3.51s)3H, (4.23d + 4.57d)                   22%             1755, 1705.                                                                              ABq(14Hz)2H, 4.57s2H, 5.03s1H,                      --POM --POM                (5.73d + 5.83d)ABq(5Hz)2H, (5.87d                                              + 6.02d)ABq(6Hz)2H, 7.47d(4Hz)                                                 1H, 9.07s1H.                                 __________________________________________________________________________

EXAMPLE 3C Esterification in Methylthiadiazolyl series (Het=MeTdz)

To a solution of sodium salt (1 weight, 1 equivalent) in dimethylformamide (5 to 6 weights) is added pivaloyloxymethyl iodide (4 to B 5 equivalents) and stirred at the same temperature for 30 minutes to 1 hour. The reaction mixture is shaken with a mixture of ethyl acetate and ice water. The organic layer is washed with water, dried over magnesium sulfate, and evaporated to remove the solvent. The residue is chromatographed over silica gel containing 10% water to give the fraction eluted with a mixture of benzene and ethyl acetate (7:1) which is then lyophilized to afford objective product.

R=C₂ H₅, B¹ =Na→POM, B² =--Na→--POM, Yield: 60%.

IR: ν_(max) ^(CHCl).sbsp.3 3350, 1780, 1740, 1700sh cm⁻¹.

NMR: δ_(ppm) ^(CDCl).sbsp.3 0.97t(7 Hz)3H, 1.20s9H, 1.25s9H, 1.98dq(7;7 Hz)2H, 2.72s3H, 3.27t(7 Hz)1H, 3.53s3H, (4.20d+4.53d)ABq(14 Hz)2H, 4.58s2H, 5.03s1H, (5.73d+5.83d)ABq(5 Hz)2H, (5.86d+6.00d) ABq(5 Hz)2H, 7.4brs1H.

EXAMPLE 4 Salt formation

Lyophilization

A suspension of dicarboxylic acid (6) or (7) (1 equivalent) in (10 weights) of water is mixed with powdered sodium hydrogen carbonate (2 equivalents) under ice cooling to give transparent solution (pH≈7.5), which is then purified with High-porous polymer HP-20 (product of Mitsubishi Kasei Kogyo K. K.) and lyophilized to give disodium salt (10) (0.8 weights).

Precipitation

To a cold solution of the free acid in methanol (2 to 3 weights) is added a solution of 1.8 M-sodium 2-ethylhexanoate in methanol (1 to 1.2 equivalents). After 10 to 30 minutes, the reaction mixture is diluted with a mixture of ether and ethyl acetate (2:1) to precipitate the desired sodium salt, which is collected by filtration.

By one of above methods the compounds of Table 7 are prepared.

Minimal inhibitory concentration

The disodium salts (10) showed the following minimal inhibitory concentration in the Table 8, when assayed their antibacterial activity in vitro against Escherichia coli EC-14 by serial dilution method on Mueller Hinton agar nutrient medium.

                                      TABLE 7                                      __________________________________________________________________________     Sodium salts                                                                   __________________________________________________________________________                               salt product (10)                                    No.                                                                               R   B.sup.1  B.sup.2                                                                               Het                                                                               shape                                                                               IR: ν .sub.max.sup.Nujolcm.sup.-1                                                   NMR: δ .sub.ppm.sup.CDCl.sbsp                                            .3(Hz value = J value)                  __________________________________________________________________________            --CHPh.sub.2                                                                             --CHPh.sub.2  3360, 3240,                                                                            (1.35d(8Hz) + 1.37d(8Hz)3H,             1  --CH.sub.3                                                                         --H  72%  --H   Tetr                                                                              powder                                                                              2640, 1765,                                                                            3.25q(8Hz)1H, 3.45s3H, 3.95                    --Na      --Na          1675, 1602.                                                                            s3H, 4.33s2H, 4.53s2H,                                                         5.02s1H (CD.sub.3 OD).                                   --H           3250br, 1775,                                                                          1.38m3H, 2.07s3H, 3.52s2H,              2  --CH.sub.3                                                                         --AOM     99%   Tetr                                                                              powder                                                                              1765, 1690,                                                                            4.00s3H, 4.50m2H, 4.65brs2H,                             --Na          1680, 1640,                                                                            5.08s1H, 5.78s2H(CD.sub.3 COCD.sub.                                            3).                                                                    1605.                                                            --H           3250br, 1760,                                                                          1.17s9H, 1.35br3H, 3.48s3H,             3  --CH.sub.3                                                                         -- POM   94%    Tetr                                                                              powder       3.93s3H, 4.50m4H, 5.02s1H,                               --Na          1685, 1605.                                                                            5.75s2H(CD.sub.3 COCD.sub.3).                  --H       --H           3400br, 1770,                                                                          0.93t(7Hz)3H, 1.89dq(7;7Hz)             4  --C.sub.2 H.sub.5                                                                       81%        Tetr                                                                              powder                                                                              1680, 1605                                                                             2H, 3.07t(7Hz)1H, 3.50s3H,                     --Na      --Na          (KBr).  4.00s2H, 4.39s2H, 4.57s2H,                                                     5.07s1H(CD.sub.3 OD).                   __________________________________________________________________________                               salt product (10)                                    No.                                                                               R   B.sup.1  B.sup.2                                                                               Het                                                                               shape                                                                               IR: ν.sup.KBr .sub.maxcm.sup.-1                                                     NMR: δ .sub.ppm.sup.CD.sbsp.3                                            .sup.OD(Hz value ≠ J              __________________________________________________________________________                                            value)                                         --CHPh.sub.2                                                                             --CHPh.sub.2  3400, 1768,                                                                            1.34d(7Hz)3H, 3.18q(7Hz)1H,             5  --CH.sub.3                                                                         --H  51%  --H   Tdz                                                                               powder       3.43s3H, (4.30d + 4.52d)ABq                    --Na      --Na          1670, 1605.                                                                            (14Hz)2H, 4.50s2H, 4.98s1H,                                                    9.36s1H.                                       --H       --H           3400, 1765,                                                                            0.94t(7Hz)3H, 1.87dq(7;7Hz)             6  --C.sub.2 H.sub.5                                                                       quant      Tdz                                                                               powder       2H, 3.01t(7Hz)1H, 3.42s3H,                     --Na      --Na          1670, 1605.                                                                            (4.33d + 4.57d)ABq(14Hz)2H,                                                    4.50s2H, 4.98s1H, 9.37s1H.                     --H       --H           3400, 1768,                                                                            0.90t(7Hz)3H, 1.2-2.0Om4H,              7  --C.sub.3 H.sub.7                                                                       quant      Tdz                                                                               powder       3.26t(7Hz)1H, 3.43s3H, (4.33                   --Na      --Na          1670, 1605.                                                                            d + 4.56d)ABq(14Hz)2H, 4.50s                                                   2H, 4.98s1H, 9.36s1H.                   __________________________________________________________________________

                  TABLE 8                                                          ______________________________________                                         MIC of Sodium salts                                                            Het═Tetr     Het═Tdz                                                                     MIC                    MIC                                                     (μg/                (μq/                               No.  R            ml)    No.  R          ml)                                   ______________________________________                                         1    --H          1.56   1    --CH.sub.3 0.39                                  2    --CH.sub.3   0.2    2    --C.sub.2 H.sub.5                                                                         0.2                                   3    --C.sub.2 H.sub.5                                                                           0.1    3                                                     n-C.sub.3 H.sub.7                                                                   0.2                                                                       n-C.sub.3 H.sub.7                                                                   0.1          4                                                            n-C.sub.4 H.sub.9                                                                   0.39                                                                      5                                                                              i-C.sub.3 H.sub.7                                                                   0.39         5      --CH.sub.2 CH═CH.sub.2                                                          0.39                                             6                                                                              i-C.sub.4 H.sub.9                                                                   0.39                                                                      7                                                                              n-C.sub.6 H.sub.13                                                                  12.5                                                                      8    --CH.sub.2 CH═CH.sub.2                                                                  0.2                                                          ______________________________________                                    

EXPERIMENT

Five representative compounds in the preceding examples are assayed for protection of mice from infection caused by Pseudomonas aeruginosa to give the effects as in the following table.

                  TABLE 9                                                          ______________________________________                                          ##STR18##                                                                                  two subc. inj. (given mg/kg each) 1 and 5                         ED.sub.50                                                                                   hrs after intraperitoneal inoculation                                                  P. aeruginosa                                             Comp. No.  R.sup.1    Het*     CN-5* PS-24**                                   ______________________________________                                         1          CH.sub.3   Tetr     22.3  11.1                                      2          C.sub.2 H.sub.5                                                                           "        22.2  17.7                                      3          CH.sub.3   Tdz      33.8  12.6                                      4          C.sub.2 H.sub.5                                                                           "        32.5  15.5                                      5          n-C.sub.3 H.sub.9                                                                         "        39.3  10.4                                      Refer- ence                                                                                ##STR19## Tetr     44.5  20.4                                      ______________________________________                                          *inoculation = 7 × 10.sup.3 -                                            **inoculation = 1 × 10.sup.4                                        

What we claim is:
 1. A compound of the following formula ##STR20## wherein R is C₁ to C₆ -alkyl, C₂ to C₅ -alkenyl, C₂ to C₅ -alkynyl or C₁ to C₂ -alkylthio-C₁ to C₂ -alkyl;Het is a member selected from the group consisting of 2-methyl-1,3,4-thiadiazol-5-yl, 1-methyl-5-tetrazolyl, and 2-thiadiazolyl; and B¹ and B² each is (1) a hydrogen atom, (2) an ester protecting group selected from the group consisting of mono- or di-cyclic aralkyl, C₄ to C₁₀ -tertiary alkyl, C₁ to C₁₀ -β-haloalkyl and C₃ to C₈ -β-alkylsulfonylalkyl, (3) a pharmaceutically acceptable ester selected from the group consisting of straight or branched chain C₃ to C₁₉ -alkanoyloxyalkyl, C₃ to C₆ -alkoxycarbonyloxyalkyl, C₄ to C₆ -tertiary alkyl, C₇ to C₁₃ -aralkyl and C₇ to C₉ -aryl, and (4) a pharmaceutically acceptable salt forming atom or group.
 2. A compound according to claim 1 wherein R is C₁ to C₃ -alkyl.
 3. A compound according to claim 2 wherein R is methyl or ethyl.
 4. A compound according to claim 1 wherein B¹ or B² is a light metal atom.
 5. A compound according to claim 4 wherein B¹ or B² is sodium.
 6. A compound according to claim 1 wherein the ester group is C₂ to C₅ -alkanoyloxy-C₁ or C₂ -alkyl, phenyl or phthalidyl.
 7. A compound according to claim 6 wherein the ester forming group is acetoxymethyl or pivaloyloxymethyl.
 8. A compound according to claim 1 wherein R is C₁ to C₃ alkyl and B¹ and B² each is hydrogen, a pharmaceutically acceptable salt or a pharmaceutically acceptable ester group as defined in claim
 1. 9. A compound according to claim 8 wherein B¹ and B² each is hydrogen or sodium.
 10. A compound according to claim 8 wherein B¹ or B² is C₂ to C₅ -alkanoyloxy-C₁ to C₂ -alkyl.
 11. A compound according to claim 8 wherein B¹ and B² each is hydrogen or sodium.
 12. A compound according to claim 8 wherein B¹ or B² is acetoxymethyl or pivaloyloxymethyl.
 13. A compound according to claim 11 or claim 12 wherein R is methyl or ethyl.
 14. An antibacterial composition comprising an antibacterially effective amount of a compound according to claim 1 as an active ingredient and a pharmaceutically acceptable carrier therefor.
 15. A method for treating or preventing human or veterinary bacterial infection caused by sensitive bacteria by administering an antibacterially effective amount of a compound according to claim
 1. 